PSI - Issue 5
Przemyslaw Strzelecki et al. / Procedia Structural Integrity 5 (2017) 832–839 Przemyslaw Strzelecki et al. / Structural Integrity Procedia 00 (2017) 000 – 000
838
7
Material
C45+C
42CrMo4
S355J2+C
1.4301
Model
I
II
III
I
II
III
I
II
III
I
II
III
m A
7.8
9.5
5
7.6
9.1
5
9.5
9.4
5
24.6 63.4
8.6
5
25.7
30
-
26.2
30.2
-
30.3
30.1
-
25.5
-
1.7∙10
6.7∙10 4
8.7∙10 4
8.4∙10 5
6.7∙ 10 4 427
2∙10 5
N 0
10 6
-
10 6
10 6
-
10 6
6
S e [MPa]
310
332
394
- - - -
440
523
359
359
- - - -
189 16.1 511 441
250
m'
- - -
-
-
-
-
- - -
-
-
-
S u from HB S y from HB
830 696
789
1130
1047
904 753
853
500
-
924
-
-
-
Table 4. Values estimated for tested materials.
Material
S235JR
AW-6063 T6
C45+C Kt=1.99
42CrMo4 Kt=1.99
Model
I
II
III
I
II
III
I
II
III
I
II
III
m A
8.2
10.1 28.7
5
7.1
9.6
5
4.2
4.9
5
6.1
4.8
5
23.9
-
19.9
24.2
-
15.1
27.2 10 6 167
-
20.3
17.2 10 6 221
-
6∙10 5
3.1∙10 8
6.7∙10 4
N 0
- - - - -
10
- - - - -
10 6
- - - - -
- - - - -
8.7·10 4
6
S e [MPa]
172
204
79 24
100
198
263
m'
-
-
-
-
-
-
-
S u from HB S y from HB
413 360
408
198 176
200
830 696
789
1130
1047
-
-
-
924
-
Table 5. Values estimated for material from literature.
Material
1045 from Aviles et al. (2013)
SUS630 from Mohd et al. (2015)
2024 T351 from Mayer et al. (2013)
Model
I
II
III
I
II
III
I
II
III
m A
8.1
9.3
5
8.8
15.3 49.5 10 6 693
5
9.2
9.6
5
26.5
30.2 10 6 393
-
30.8
-
27.2
27.2 10 6 165 18.2 413 360
-
1.1∙10
7.1∙10 4
1.1∙10 6
1.4∙10 5
9.5∙10 7
6∙10 5
N 0
6
S e [MPa]
352
468
651
629
120 25.3
204
m'
- - -
-
-
- - -
-
-
-
S u from HB S y from HB
998 825
935
1385 1110
1258
- -
408
-
-
-
4. Summary and conclusions
From the analysis presented it may be deduced that it is possible to exactly evaluate fatigue strength using model II. The use of model III should be deemed as not recommended. The reason for this fact may be assuming fixed value of m slope in model III. The assumed value 5 is significantly lower than the experimental values; only for the notched elements was this value close to the experimental value. Moreover, in model III, the dependency determining the base number of cycles N k estimated this value to be much below the experimental value. With model II, estimating life for three materials (1.4301, AW-6063 T6, 2024T351) was unsatisfactory. Estimating the tensile strength and yield strength from the hardness measurement may be deemed as satisfactory - except for the materials for which the S y to S u relationship assumes extreme values. These materials may be deemed as plastic (for low S y / S u values), or brittle (for high S y / S u values), which suggests that the relationships (1), (2) and (3) are good approximations for elastic-plastic materials. The above observation may be found in the PN-H 04357 (1993),
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